Lend me your brains...

[Jes-ka]

I am beginning a new project soon and I need some information to start with. Basically, I want to write a book about physics. Not like crazy physics, but the physics that everyone needs to know about... the stuff that is relevant to people in the everyday world.

So, I turn to you fine people and ask that you post any questions you can think of that have to do with 1) physics and 2) your everday life.

An example would be the most common questions "why is the sky blue" or "why does my car window fog up when it's cold outside"... and so on. I have chapters broken down by topics 1) the human body, 2) the automobile, 3) the home, 4) nature, 5) Earth, 6) the solar system, 7) the Milky Way, and finally 8) the universe (if it makes it this far).

Anything will help. I am going to compile the questions and use them to address all of these common queries in hope of writing a sort of handbook for those who want to understand the world itself but cannot really grasp the finer concepts of physics. Naturally, I have some thoughts composed already but some things may not be relevant to the general populace (such as why photons have no mass), so this will help me get an idea of where to steer my ramblings.

So.. whatever comes to mind... ask it here! Thanks in advance. :)

[Ghengis John]

Sounds fascinating. Kind of reminds me of "As far as the eye could see" by Issac Asimov. Here's one from my life. My mom is amazed at how the microwave works. I tell her, it makes food hot by speeding up the water molecules in it. She asks why pots and pans have a problem with the microwave. I have no idea. So: "Why isn't metal safe to use in the microwave?" . I hope that helps and I'd like to know.

[Michael Ubaldi]

Ambitious and admirable, Jes. (I submit these out of pertinence, not ignorance.)

1. Why can't I back my car out of the mud?

2. Why do I need to pump the brake pedal when my car slides in snow or ice?

[Jes-ka]

Sounds fascinating. Kind of reminds me of "As far as the eye could see" by Issac Asimov. Here's one from my life. My mom is amazed at how the microwave works. I tell her, it makes food hot by speeding up the water molecules in it. She asks why pots and pans have a problem with the microwave. I have no idea. So: "Why isn't metal safe to use in the microwave?" . I hope that helps and I'd like to know.

I guess I will answer them too... :P

A microwave works like this: microwaves (specifically radio waves) pretty much ignore plastic and other microwave safe materials, but the water absorbs these radio frequencies like a sponge and, as you said, react to the water molecules (their momentum energy actually gets turned into heat energy!). However, they cannot pass through metal. They get reflected, and so the waves cannot reach the food to heat it up. Definitely not good for cooking efficiency.

I have these plates a friend gave me, and when I heat my taquitos on them, the dish gets warm. Not a good sign! Microwave safe = will not heat up from bombardment by microwaves. So what happened? There is something mixed in the ceramic (or maybe even the glaze :( ) that is metallic. How do I know that? Well...

It is said that putting metal in a microwave isn't safe. This is because you can get an electrical current in the metal, and once enough builds up... it arcs, aka it reaches out to the metal parts of the microwave which are grounded (similar to lightening striking grounding rods in homes).

Anytime you get current moving through a metal, it warms up. Certain metals will heat up faster, which is why it is always bad news to use aluminum foil in a microwave. It is highly flammable and is guaranteed to either catch fire or ruin your microwave.

Which leads me to another thing. My mom always left a cup of water in the microwave. She said it was in case a little one started pushing the buttons and turned it on, and in the event nothing was inside the microwave would cook itself. This is true. If there is nothing inside the box to absorb the waves, they will bounce off the walls and eventually make it back to the magnetron (the thing that creates the waves). And that's all bad.

[the Brayn]

One that I always forget is what is the terminal velocity of a human being and what is the maximum distance a person can fall and still survive. These are important questions.

[TheBadFish]

Jes is a smarty pants!!! What a cool idea for a thread this is. Are you covering Atmospheric physics as well? :D

[the Brayn]

Jes is a smarty pants!!! What a cool idea for a thread this is. Are you covering Atmospheric physics as well? :D

Wouldn't that fall under one of the nature/Earth headings? I figured it would since this is primarily to be used in a physics in everyday life type of situation so people wouldn't be too worried about extraterrestrial atmospheres.

[Jes-ka]

I want to answer what anyone might wonder to themselves... which would probably include atmospheric physics. At least... in a very basic question. Maybe like... what is it with hail, man?

[Cacophany_cat]

This is a fantastic idea Jes! I wish you all the luck in the world with it <3

Hmm, some basic ones:

Why is hair static when warm air is applied to it?

Why are sunsets red and orange?

Why are you able to stay on a bike while it's moving but not when it stops?

[dropK1CK_ninJA]

Jes is a smarty pants!!! What a cool idea for a thread this is. Are you covering Atmospheric physics as well? :D


We all know Geology is where it is at!

[Jes-ka]

Ambitious and admirable, Jes. (I submit these out of pertinence, not ignorance.)

1. Why can't I back my car out of the mud?

2. Why do I need to pump the brake pedal when my car slides in snow or ice?

1) I have little personal experience driving in mud, but anything slick affects friction, which is what propels your car to begin with. Without friction, your wheels would just spin in place. So if you have been stuck in the mud, and your wheels just spin and spin... that means... loss of friction! Or "traction" as car people say.

So, I read online about how people get themselves out of the millions of types of mud. It sounds like once you lose traction, meaning you stopped moving the tires, your car doesn't have the power to overcome it. You need some kind of outside force to pull you out (i.e. another car) or a winch.

One clever solution by folks who regularly get themselves stuck: have 2x4 or 4x4 boards to stack under the wheels as you jack up the car. The boards replace the slippery mud surface and allow your wheels to move again.

Does this answer that question? I'm not sure.

2) This is something I do know. Before the days of anti-lock brakes, if you suddenly slammed on the brake pedal the brake pads were squeezing so hard against a surface that is moving incredibly fast, and that means LOTS of friction between the pads and the metal.. thing (excuse my lack of terminology). Rub you hands together as hard as you can and you get... what? Lots of HEAT. And that is really bad because the heat between the pads and the metal is so high that they fuse together. Yes, the pads that slide freely around the metal thing have now become one... and that means your wheels stop turning. (Or something breaks off, either way your brakes are pretty much useless)

So, that's good right? You can stop now? Not really. You were already moving, and Newton's laws say an object in motion tends to stay in motion (especially on a frictionless surface such as ice). That means your car! You are now sailing across the ice or snow, subject to whatever objects are in your way. In case you are wondering, this is bad.

How can one avoid such a terrible thing? Pump the brake pedal. Why? Because applying friction in short periods prevents the temperature between the pad and the metal from getting too hot (and subsequently fusing), thus allowing your brakes to continue working.

Nowadays there are anti-lock brakes. If you have them, they do the pumping for you if you happen to suddenly push the brake pedal to the floor. Cars are designed to notice how fast and how hard you push on the pedals, so you don't have to think "am I breaking hard enough to lock my brakes?" Which, is awesome.

[Jes-ka]

One that I always forget is what is the terminal velocity of a human being and what is the maximum distance a person can fall and still survive. These are important questions.

1) Terminal velocity can be a tricky thing. It depends on several things, like how much the falling object weighs, and if you are talking about Earth gravity or Moon gravity.

In essence, this terminal velocity is a limit of speed that a falling object reaches as it falls. More simply, the speed at which you stop accelerating.

Let's say you jump off a boat into the ocean. You sink (or fall really slowly), but after a bit you sink at a very specific speed based on how much the water interferes. You cannot suddenly sink faster because the water is basically getting in the way the same no matter what depth you reach. The same can be said for skydivers. Air is much easier to fall through, so you fall much faster! However there is a point where air resistance prevents you from falling any faster and so you fall at a constant speed (ahem, the terminal velocity).

Wikipedia says the world record for the fastest has been recorded at 382mph (614 km/h).

The most important thing to consider when free falling is your surface area. Are you diving? Are you spread eagle? The funny positions sky divers make help them fall faster or slower because of how much surface area they expose to the air resistance. Greater surface area = greater resistance = slower velocity.


2) There are some who have managed to survive failing parachutes and plane crashes. The success rate isn't that high, but I did find an interesting (and somewhat disturbing) article on what you can do if faced with such a situation. You can read that here (http://www.greenharbor.com/fffolder/carkeet.html).

I've heard of kids falling out of two-story buildings without a scratch. It all depends on the situation.

[Jeremy Steeves]

Awesome idea you've got Jes-ka!

I enjoyed that modern humorist read.

[Jai]

When I first read the title I thought it referred to zombies. :confused:

Question: What really happened to Schrodinger's cat?

[Jes-ka]

This is a fantastic idea Jes! I wish you all the luck in the world with it <3

Hmm, some basic ones:

Why is hair static when warm air is applied to it?

Why are sunsets red and orange?

Why are you able to stay on a bike while it's moving but not when it stops?

1) I'm not sure I understand this question. Can you phrase it differently?

2) Light has no choice but to travel through the atmosphere to get to us. In a sunset, the length of atmosphere is greater than when the sun is at high noon.

The color of sky we see is determined by scattering. Certain colors of light get scattered and others don't, causing a separation of color. The sky is blue at noon because the blue colors are scattered from the rest and knocked around everywhere in all directions until they eventually reach your eyes, while the other colors all travel in the same direction (toward you) and cause the sun we see to be yellow.

Have you ever noticed during the day that the sky is a lighter blue near the horizon? It has so far to reach you at that distance that barely enough make it to your eyes to be blue enough. In a sunset, because the source of light is now even further away, almost NO green, blue or violet light will make it to your eyes because it got scattered too much. These colors have smaller wavelengths, and therefore are a bit ADD when it comes to traveling far distances. They get scattered so much they never travel in a straight line from the source to your eye.

Reds and oranges are long wavelengths, and therefore more calm and steady and will always be able to make that trek to your eyeballs.

3) Bikes are pretty complicated nowadays. Chris' brother works in a bike shop and they have a weird language when it comes to talking about how a bike moves. Most of it relates to the physics of how bicycle design works, but as far as the difference between moving and not moving, I think I can answer that.

When you stand with your bike, it needs a stand to stay upright. There is a general rule for determining if something will tip over. The center of mass has to be directly above it's base. But the base is only as large as what touches the ground. So with a bike, we are talking about the thin line the tires make. You could theoretically balance a bike if you could get it just right over this base, but since its so awkward a shape, this is really hard.

When you ride a bike, something really amazing happens. It goes from just something that tips over easily to an angular momentum machine! Anytime something rotates, it acts like a gyroscope. A gyroscope is weird but the basics of that is if it spins fast, it has a ton of "angular momentum". If you try to tip it over, all that angular momentum counters it and balances it out.

Here's an animation from wikipedia if what I said doesn't make sense.

http://upload.wikimedia.org/wikipedia/commons/2/26/Gyroscope_wheel_animation.gif

The wheel spins, but then some force tries to tip it over. The angular momentum of the wheel keeps it upright. I fear saying anything more complicated... so just let me know if you want more detail.

[Jes-ka]

When I first read the title I thought it referred to zombies. :confused:

Question: What really happened to Schrodinger's cat?

http://icanhascheezburger.files.wordpress.com/2007/09/128338532260781250iminurbocks.jpg

His cat is alive. Maybe.

I get asked about this a lot, actually. Some people are really confused by the concept of Shroedinger's cat.

Summary: Schroedinger came up with a way to represent states for electrons. He used a cat enclosed in a box with a device that would, based on statistics, produce a deadly gas that would either 1) kill the cat or 2) not kill the cat.

What is most important to know about this thought experiment: You do not know anything about what "state" the cat is in (alive or dead), until you observe the cat by opening the box.

In quantum mechanics, it is the same for electrons. It was found that using fancy math, electrons have many possible states, each represented by their own equations.

A simplified example would be akin to solving "polynomials" in algebra class. If you have one that looks like x to the third power, that means there are 3 solutions for the polynomials. In quantum mechanics, the idea behind the math is similar, but a little more complicated. You know that you have some given number of possible states that your electron can be in, just like there are two states the cat can be in.

So, the funny thing is that the electron will only pick one state to be in once we observe it. Out of 2 or 3 possible ways to exist, it only chooses one when we are watching. Otherwise, we have no idea what it is doing.

My classmates got together one day and we asked our professor "what is the electron doing before we observe it?" They told us that until we observe it, that electron doesn't even exist! Insane!

[Jai]

:p I already know all that, though.

[the Brayn]

I don't know, that Shroedinger fella doesn't sound very smart to me. You could always just shake the box while the cat is inside to see if it is still alive. ;)

[TheBadFish]

Why is it colder at night if there are no clouds in the sky and yet hotter during the day if there are no clouds in the sky?

[Ghengis John]

My classmates got together one day and we asked our professor "what is the electron doing before we observe it?" They told us that until we observe it, that electron doesn't even exist! Insane!

Silly, egotistical scientists. :D

Thanks for answering my question as well Jeska.

[Jes-ka]

Why is it colder at night if there are no clouds in the sky and yet hotter during the day if there are no clouds in the sky?

I expected a question like this from you! :P

So, why is it colder at night without clouds compared to when there are clouds? And why is it hotter without clouds during the day than with clouds?

One could figure from this that clouds act as insulators...which is very true! Clouds act like blankets for our planet to prolong the snuggly warmth after the sun has gone down, and then like a shield to block out sunlight (and the resulting heat that goes with it) when the sun comes back up. It's perfect!

Without clouds, no life or vegetation would be able to survive! Which is why scientists are studying how clouds effect Global Warming.

[Jes-ka]

I don't know, that Shroedinger fella doesn't sound very smart to me. You could always just shake the box while the cat is inside to see if it is still alive. ;)

If you shake the box with the cat, and the cat is alive, does shaking it kill the cat?

[TheBadFish]

I expected a question like this from you! :P

So, why is it colder at night without clouds compared to when there are clouds? And why is it hotter without clouds during the day than with clouds?

One could figure from this that clouds act as insulators...which is very true! Clouds act like blankets for our planet to prolong the snuggly warmth after the sun has gone down, and then like a shield to block out sunlight (and the resulting heat that goes with it) when the sun comes back up. It's perfect!

Without clouds, no life or vegetation would be able to survive! Which is why scientists are studying how clouds effect Global Warming.



hahahaha I had to test your credentials Jes...you know that :P

[Jes-ka]

I have a question for you, Mister Fish.

Why is it that some storms have warm fronts and others have cold fronts?

[TheBadFish]

Well, the question itself is rather vague, but I think I understand whatcha asking. In the United States, we recognize 4 different types of fronts:Warm,Cold,Occluded,Stationary. They are all generally associated with conditions favorable for thunderstorm development, however I will talk specifically about cold and warm fronts as they were the subjects in question. The major difference between the two is which air mass, cold or warm, displaces the other air mass. If cold air is moving into warmer air, then we have a cold front where the two masses meet. Similarly, if warmer air is moving into a colder region, we have a warm front. So what do these inundations of air masses have to do with storms? Well for a storm to occur there must be something we in atmospheric physics like to call instability. Think of this instability as the lifting of airparcels so that clouds are able to form..... Unstable environment = clouds & precipitation Stable environment = clear skies & no precipitation. So in the case of a cold front we have that heavy cold air running straight into light warmer air. Obviously the cold air will force that warm air upward. Voila....instability. Well what about in the case of the warm front....how can the warm air force that colder air upward? Well it can't! In fact, the warmer air rides up the colder air like a skateboarder up a ramp. So again we have upward motion and thus..storms.

Also, not all storms will be involved with warm fronts or cold fronts. Lake effect storms, windward mountainside storms, and coastal fire-ups are just a few eamples of non-front related storm situations.

P.S. I <3 Clouds

[DreadNemesis]

It took me a while but I've thought up some questions for you Jes:

1.Why do some appliances have 2 prongs on their cords and some have 3?

2.How does the amount of voltage going into a lightbulb affect how bright it is?

3.What exactly is fire?

4.Why can't I see the stars at night in the city?

[Jes-ka]

Well, the question itself is rather vague, but I think I understand whatcha asking. In the United States, we recognize 4 different types of fronts:Warm,Cold,Occluded,Stationary. They are all generally associated with conditions favorable for thunderstorm development, however I will talk specifically about cold and warm fronts as they were the subjects in question. The major difference between the two is which air mass, cold or warm, displaces the other air mass. If cold air is moving into warmer air, then we have a cold front where the two masses meet. Similarly, if warmer air is moving into a colder region, we have a warm front. So what do these inundations of air masses have to do with storms? Well for a storm to occur there must be something we in atmospheric physics like to call instability. Think of this instability as the lifting of airparcels so that clouds are able to form..... Unstable environment = clouds & precipitation Stable environment = clear skies & no precipitation. So in the case of a cold front we have that heavy cold air running straight into light warmer air. Obviously the cold air will force that warm air upward. Voila....instability. Well what about in the case of the warm front....how can the warm air force that colder air upward? Well it can't! In fact, the warmer air rides up the colder air like a skateboarder up a ramp. So again we have upward motion and thus..storms.

Also, not all storms will be involved with warm fronts or cold fronts. Lake effect storms, windward mountainside storms, and coastal fire-ups are just a few eamples of non-front related storm situations.

P.S. I <3 Clouds

Dude, that is awesome. :D

[dropK1CK_ninJA]

Which came first, the chicken or the egg?

[Ghengis John]

Not a physics question.

[dropK1CK_ninJA]

Psh.

Okay! How about this one!?

Why is each snow flake a different shape yet we call ice a mineral because it has the following criteria: set chemical comopostion, occurs naturally, a set crystalline structure. If it's structure is consistant across the board, why is each snowflake built differently?

[Dayfish]

My Head Is Asploding.

[Jes-ka]

Sorry for any delays, I'm sick and I'm sure you don't want an incoherent explanation. Unless they were already that way. :P

[Jes-ka]

1.Why do some appliances have 2 prongs on their cords and some have 3?

I managed to answer one out of your half million questions, Dread. The others will come in due time. Pwomis!

First, what are those prongs for anyways? They connect the wire inside the cord to the wires in the wall so electricity can travel to the appliance. You will always see 2 prongs, minimum. Why? Because electricity must go in one way and out the other. It's like a freeway that has both on-ramps and off-ramps. One contact is "hot" (electricity uses this prong to reach the appliance, or the on-ramp) and the other is usually "neutral" (the electricity returns to the wall, or the off-ramp). Electricity travels through wires just like water flows through pipes: if it's going in one way, it will have to come out another way.

So, why the third prong? That prong represents a wire that grounds the appliance to the earth once it is plugged into the wall. My mom's house does not have any outlets with a third hole, which means that none of the outlets are "grounded". Grounded means there is literally something that, in the event of something going wrong, electricity can travel to the earth via the grounding wire and prevent surges or fires. Grounding basically allows the electricity to reroute itself to prevent harm to your appliance or your home. It's not exactly a requirement for cords, but in this day and age of high-tech appliances, it's necessary.

The third prong is connected to a wire inside the cord. That wire is attached to the neutral wire at some point along the cord, so if for some reason there is a break in the neutral wire (the off-ramp), that electricity can still escape back into the outlet and into the ground. Without it, it's like setting loose a bunch of headless chickens with razor blades instead of feathers. Painful, fast and outta control!

[Magiz]

So, Jes-ka...why am I able to do this on certain days of the year?

http://farm3.static.flickr.com/2199/2186977150_95027c3b84.jpg

[Dayfish]

So, Jes-ka...why am I able to do this on certain days of the year?

http://farm3.static.flickr.com/2199/2186977150_95027c3b84.jpg

You're such a freaking dork face.

[DreadNemesis]

Jes are you still doing these? Because I have more questions for you.

[RocksYerSocks]

Well, the question itself is rather vague, but I think I understand whatcha asking. In the United States, we recognize 4 different types of fronts:Warm,Cold,Occluded,Stationary. They are all generally associated with conditions favorable for thunderstorm development, however I will talk specifically about cold and warm fronts as they were the subjects in question. The major difference between the two is which air mass, cold or warm, displaces the other air mass. If cold air is moving into warmer air, then we have a cold front where the two masses meet. Similarly, if warmer air is moving into a colder region, we have a warm front. So what do these inundations of air masses have to do with storms? Well for a storm to occur there must be something we in atmospheric physics like to call instability. Think of this instability as the lifting of airparcels so that clouds are able to form..... Unstable environment = clouds & precipitation Stable environment = clear skies & no precipitation. So in the case of a cold front we have that heavy cold air running straight into light warmer air. Obviously the cold air will force that warm air upward. Voila....instability. Well what about in the case of the warm front....how can the warm air force that colder air upward? Well it can't! In fact, the warmer air rides up the colder air like a skateboarder up a ramp. So again we have upward motion and thus..storms.

Also, not all storms will be involved with warm fronts or cold fronts. Lake effect storms, windward mountainside storms, and coastal fire-ups are just a few eamples of non-front related storm situations.

P.S. I <3 Clouds

I asked him this question once too... except I got all the fronts ... not just the simplified Cold and Warm from versions :) Yeah it took about an hour to explain. Thanks to him I also know why mountain weather is different than most. :)

[Jes-ka]

Jes are you still doing these? Because I have more questions for you.

Yes. I realize now you had like a million and I answered one. lol

[Jes-ka]

I will answer this one now since it is easy. Please ask any follow-up questions if I am too vague.

So, Jes-ka...why am I able to do this on certain days of the year?

http://farm3.static.flickr.com/2199/2186977150_95027c3b84.jpg

That is a myth actually. I had to look up what this myth entails and here is what I found:

"The balancing act is repeatable only on the vernal and autumnal equinox, when the sun crosses the equator, making night and day equal on all parts of the earth."

But honestly this is not true. The force due to gravity will always be 9.8 m/s^2 no matter where it is in orbit about the sun.

[Mookel]

So, Jes-ka...why am I able to do this on certain days of the year?

http://farm3.static.flickr.com/2199/2186977150_95027c3b84.jpg

WITCHCRAFT! :eek:

[Jes-ka]

Was that the answer? lol

[Jes-ka]

What exactly is fire?

Well, this is a tough question to answer. I will start with what you see when you look at a flame. You see something, right? Light that flickers and ranges in colors from yellows to reds. Sometimes with a gas stove you even see blue flames (I'll explain later). The light is emitted by photons, because that will always and forever be what light is.

As you watch the flames, you are not watching a thing...[/I]you are witnessing the changing of states.

In physics, we study how compounds move from one state to another while keeping track of caloric energy and mass, etc. Caloric energy is basically how much energy exists in an object (the amount of energy it would release if you set it on fire). The longer something burns, the more caloric energy it has stored inside.

So, just like ice melts from liquid to solid... solid things can catch fire and part of it will escape into the air as a gas and the rest remains solid, but of a different nature. Whenever compounds change into something else, meaning molecules have moved themselves around and exchanged places with others, a chemical reaction has occurred.

But that's only a third of it! I think just about everyone learns through practice or education that fire needs oxygen to thrive. Fire also needs to involve materials that are combustible. Combustible (aka flammable) materials are considered "unstable". If you get fire near it, it is guaranteed to catch on fire. But why?

Fire has a temperature, and that temperature can vary. If you have ever heard of a "cool" flame, that just means it is on the lower end of a temperature range... but it's still hot to us!

So, back to catching things on fire... every object has something called a "fire point". This is a temperature at which a flammable material will catch fire and continue to burn (the "flash point" is when it will ignite, but stop after the source of ignition is taken away).

Now what... hmmm... oh yes, the fire point. If you already have a flame that is equal or above the fire point of some item, and you have oxygen, then you will most likely catch the item on fire. But since this is merely a change of state, how is it that fire spreads?

When you strike the match stick against the side of the box, that side is rough in order to create friction. Friction produces heat. When the space capsules would slow down for re-entry into our atmosphere, it was to reduce the friction of the gas molecules on the side of the capsule. They could withstand a certain amount of heat from the friction, so as long as they controlled their descent they were okay. But what did they see out their window? FIRE!!

All you need to make fire is to do something that produces enough heat to reach the fire point of something and sustain it with oxygen and more things to burn.

This is somewhat disorganized because there is so much to this question, so if I miss something you were hoping to hear about just let me know.

Fire is just energy. We see it because photons emit light that hit our eyes. But why do we get photons out of the tip of a match stick? Electrons start to get agitated when energy is given to them. When you warm something up on the stove, you are give energy to the pot, which then gives that energy to the water or food inside. This energy is freely exchanged simply because the pot is in contact with the flame, and the food is in contact with the pot.

Anything can "accept" energy, but if you give something enough energy, it begins to glow. Electric stoves do not use open flames, they simply let a metal coil heat up. Notice that at first it glows a dark red... then orange... then almost yellow. The color is based on what the coil is made of, but the fact that it glows at all should tell you how much energy is flowing through it. How can you tell? Touch it! Okay, don't really touch it, you would be hurt by how much energy was released unto your poor hand.

Which brings us back to when I said that things have caloric energy. That is why so much can come out so fast and hurt us by burning our skin or catching other things on fire.

Fire is the somewhat disembodied caloric energy that comes from something combustible. It is not a thing in itself, which is quite confusing. It is just a reaction that can happen to things.

Man... I'm worn out. lol!

[dropK1CK_ninJA]

On that same vein of thought, and this could be an explosive question but:

How do we define life?

[Ninja Raiden]

Is that physics?

Um, physics question (maybe)... what happened all that hullabaloo over the "hole" in the ozone layer?

[dropK1CK_ninJA]

Is that physics?

Um, physics question (maybe)... what happened all that hullabaloo over the "hole" in the ozone layer?


Ah I guess you are right. That is more of a biological question. Ha!

My bad.

[Jes-ka]

Ah I guess you are right. That is more of a biological question. Ha!

My bad.

Yeeeah... physics is just about how everything works. :P

[dropK1CK_ninJA]

Yeeeah... physics is just about how everything works. :P

Let us discuss Sun Spots and how the affect us on the planet. Of course this is a multipart question that requires discussion of what sun spots are, their origins, our different spheres of protection and finally what gets to us ...

Whew!

[Mookel]

Was that the answer? lol

Well if your physics fails to explain it, witchcraft is obviously the next logical answer :p

[Jes-ka]

Let us discuss Sun Spots and how the affect us on the planet. Of course this is a multipart question that requires discussion of what sun spots are, their origins, our different spheres of protection and finally what gets to us ...

Whew!

I gotta address Dread's other questions first!

Such as... why we cannot see the stars at night in a city.

First, a story! A long time ago in a galaxy far, far away.... okay, not really.

Once I went camping with some friends. We all went to high school together in a small rural town in the "Greater Sacramento Area". Someone wanted to go camping and so I helped them pick a place that was in the middle of nowhere up the mountain towards Tahoe. I had not realized until we arrived at the campsite that I was the only one with real camping experience.

I knew it when we took a walk down to the lake to watch the meteor shower. You could hear the realization in their breathe as we walked towards a clearing. They were really taken aback as the pine trees opened up to a sky filled with billions of stars. They didn't even care about the shower because of how amazingly beautiful it was. One girl asked what the huge blotchy part was. I felt so bad for them. No one knew what it was except for me. They were staring at the Milky Way!

When you grow up with a sky that either has no stars or just the brightest ones that make up constellations like Orion, Perseus, the Pleiades, and the Big Dipper, you miss out on what the sky really looks like! That is why when city lights are so bright that it interferes with how far we can see, it is called light pollution.

Light pollution is really a bad thing when you think about it, because it is affecting animals as well as humans. Migratory animals cannot see important stars that they used in the past to navigate their way home.

Light pollution is caused by too much light. Many cities have regulations, such as requiring all street lamps to point downward, or limiting the wattage of the bulbs that are used at night. But it is more than just the power of each light that makes a difference, it is how many over an area, and whether or not there are stadiums nearby, et cetera.

My physics building at Uni was right next to a stadium. It was really hard to do any stargazing from the room with the stadium lights on, but astronomy classes had to deal with it.

Star light isn't all that strong... just enough for a small speck to reach our eyes. Take a flashlight outside one evening and shine it at the stars. Even a flashlight makes a difference in the intensity of the stars!

Check out the image I attached to this post. You can see how the city of San Francisco glows at night. If you go to page 2 of this thread, you can read a post I made about sunlight. Well, the glowing is the same effect as if the sun was shining through the air. The light has to travel through our atmosphere, just from a different source!

Imagine how powerful the sun is... and that prevents us from seeing any stars other than our own. It even makes our sky a blue color instead of black.

So my conclusion is that I like to ramble, and that we cannot see stars in a city because lights make the atmosphere glow.

[Jes-ka]

Let us discuss Sun Spots and how the affect us on the planet. Of course this is a multipart question that requires discussion of what sun spots are, their origins, our different spheres of protection and finally what gets to us ...

Whew!

You ask some very enthusiastic questions! I have one more of dread's to answer and then I will answer yours. :P

[dropK1CK_ninJA]

You ask some very enthusiastic questions! I have one more of dread's to answer and then I will answer yours. :P

I like science!

It goes with being a geologist, I suppose.

Speaking of which, I know this is a bit of a tangent: anyone know any good mineral collection sites either public, commercial, or out in the wild within the northeast United States... that'd be awesome.

[Ninja Raiden]

Oh, I have a question! Maybe a few... (Sorry, seeing as you have Dread's and Dropkick's to deal with). These questions are inspired by your starlight explanation.

1. Why do the stars appear in a variety of colours?
2. Why do you get a sense of vertigo when you look up at the sky?
3. How do you know animals use the stars for migratory navigation?

I'm not too sure about the last one though! But I'll tell you, I used to use the Plough as a marker when I was walking home from town (about five miles). So, um, yeah...

[Jes-ka]

Dread, I'm gonna assume what I have been (hastily) writing up for you has been good enough so I will continue with the last one out of your four questions.

How does the amount of voltage going into a lightbulb affect how bright it is?

A lightbulb shines because current flows through the little filament inside, it gets super hot and glows. The brightness of the light is dependent on what the filament is made of, the temperature range that the filament can heat up to, and how much electricity it will allow through at one time (aka resistance).

Watts are how we measure how much energy a lightbulb will use. A 60 watt bulb will use less power than a 120 watt bulb. The filament will not glow as hot and therefore is not as bright.

So what about voltage? Well, first what is voltage?
************************
Voltage is ... okay just bear with me on this one ... a potential difference of electricity!!

Potential anything in physics will always imply that you have some kind of "field" or a range of values to interact with. A gravitational field will effect anything with mass that tries to move against it. Let us say you are standing near a well. You hold a ball over the well. You are doing work as you hold that ball up because of the gravity field you live in. What happens when you let go? The ball falls because it is pulled or dare I say... attracted to that end of the field.

Now imagine an electrical field. Difficult? Okay, imagine a bar magnet. One end is positive and the other is negative. The electrical field looks like the one in the image I attached to this post. Notice how there are arrows? Think of the ball "falling" down the well. The earth's gravitational field has arrows too!

So what is the point? Water wheels use gravitation potential energy to do things. They use the fact that water falls (due to a potential difference) and turns that into motion that helps turn stuff and... move lumber I guess??

Electrical potential is used in the same way, but smaller. By creating potential differences we can get current to move. Just as heat always moves from hot to cold, and apples always fall from trees to the ground, current always moves from higher potential energy to lower potential energy.

Imagine an electric charge is a go-kart. Imagine hundreds of them in a row as they all drive bumper-to-bumper through a PVC pipe raceway. The power source gives them energy/speed in one place and any energy they are given will get dissipated by interacting in various ways through the raceway.

Now add a resistor, or speed bumps in one section. Measure their energy/speed before and after the speed bumps. Since the power source only gives it speed in one place, these karts go slower after the "resistor". So were you to measure the change in speed... you would have what represents a change in potential energy.... aka the voltage!
********************************

So voltage is kind of like saying how strong the current is in a way. A light bulb is like a resistor in a circuit. But the thing is that a higher voltage will merely wear down the resistor faster than a lower voltage. It's like a road with a higher speed limit means more cars pass through. Therefore the voltage plays more of a role in the lifetime of a bulb than how bright it is.

[Michael Ubaldi]

Magnetic monopoles. Tell me about them.

Also, any juicy information on the Large Hadron Collider.

[theempyrealwordsmith]

So, i don't know whether this falls under physics (since i don't really understand it in general) but i have often wondered why, directly after yawning, i sometimes find that everything has gotten much, much louder.

[TheMFShadow]

Also, any juicy information on the Large Hadron Collider.

I second that. I would really like to know if a minute black hole can be formed and the repercussions that would follow.

[Michael Ubaldi]

I second that. I would really like to know if a minute black hole can be formed and the repercussions that would follow.Me, too. Just a few data points? Information pushing our technology forward by 200 years, a la the Protheans?

[Jes-ka]

I will address the LHC since it is such a huge concern. Enjoy. :)

What is the LHC? And also, some physics!
To start, you may want to read about the Large Hadron Collider here (http://en.wikipedia.org/wiki/Large_Hadron_Collider). In short, it is the largest of all particle accelerators and will be testing something called The Standard Model.

Recall back in the day when you (hopefully) learned about the 4 fundamental forces in the universe: Weak, Strong, Electromagnetic, and Gravitational. These four forces are how we describe any and all interactions between matter as we know it.

Each force comes with its own set of equations and even a sort of "currency" particle that gets exchanged and passed around. Gluons are for the Strong Nuclear force , photons are for the EM force, W and Z bosons are for the Weak Nuclear force, and then there are gravitons for Gravity (although we have not proven they exist yet).

In physics, we like it when one general rule applies to a lot of things. This is why there is an assumption for graviton particles. If the other three have particles... then it would make universal sense that the fourth force should too. There is also a lot of math about that too, but who cares? (jk!)

The Standard Model is an almost-all encompassing theory about those first three forces that are associated with particles. It does not include Gravity because we need those darn gravitons or whatever it may be to be observed. So, it's a "close, but no cigar" theory of all matter interactions. It also is not perfect in regards to those first three forces. There is a rather large mystery regarding this theory and the hope is that the LHC will solve it by proving the existence of yet another unobserved particle called...

*drum roll*

The Higgs Boson (http://en.wikipedia.org/wiki/Higgs_boson)! If you have read about the LHC you may have heard about this particle. I suggest perusing the Wiki link for some background (if you feel adventurous), but all that is really important about it is that the Higgs Boson would explain how things like photons (no mass, EM force) and other particles like W & Z bosons (hardly any mass, Weak force) can work together to do things.

In my opinion, this information is extremely important because it will lead us to a better understanding of what Grand Unification Theory (http://en.wikipedia.org/wiki/Grand_unification_theory) should be.

What does the LHC do?
Now, let's digress about particles. Subatomic particles are electrons, protons, and neutrons, but these are made up of Elementary particles like quarks and bosons, and these are not known to be made up of anything smaller as of yet.

There are a few different possible "ingredient" elementary particles to make a Higgs Boson, and this is the exact goal of the LHC: to cook up a particle.

In order to make certain particles, you have to shoot a few at each other and hope to see broken off parts form or decay into something you want. Imagine you have built things out of Legos (representing subatomic particles which are made up of smaller pieces), like a dinosaur, a plane, and house. Now they all have different sizes and similar parts and dissimilar parts (i.e. the pane has a propellar but the others do not). We want to make something new, but it can only be made from any combination of parts from these three things.

The problem with particles/legos is that we can only handle them as a certain size, some are not stable enough to make it down the accelerator at all, and all kinds of other annoying things.

So let's make something like... a helicopter. We can venture a guess that we would need the plane and maybe the dinosaur. We would do a crap ton of math and Feynman diagrams to work it out (purdy maps of how the parts would disassemble and then reassemble into what we want or don't want). Eventually we would find out that this is our best bet so then we decide to test it (i.e. smash them together).

You take your plane and dinosaur, send them down the accelerator which does just that, and once they reach your calculated speed... you smash them together! Pieces go flying all over, some parts may combine to make what you don't need, but at some point you may see your helicopter, if only for a brief moment. (See attached images for what it really looks like with particles. I knew a guy who had to translate what that image meant in terms of actual physics.).

Micro Black Holes & Strangelets?
There are a lot of people concerned that this new accelerator is so powerful will create a micro black hole or something equally bad and destroy all life as we know it.

I am certainly no expert on this sort of thing, but I trust that there are good scientists and mathematicians alike that have taken the time to consider the safety of all mankind. Here (http://en.wikipedia.org/wiki/Safety_of_the_Large_Hadron_Collider)is a very concise page about the safety concerns themselves.

From the article about micro black holes:
According to the [LHC Safety Assessment Group], even if micro black holes were produced by the LHC and were stable, "they would be unable to accrete matter in a manner dangerous for the Earth."[4][6] The Safety Assessment Group argues that "they would also have been produced by cosmic rays and have stopped in the Earth or some other astronomical body, and the stability of these astronomical bodies means that they cannot be dangerous."[4]

Meaning, if the LHC could create them they are just as easily created near us via cosmic rays, and we are still alive!

From the article about strangelets:
...the probability of the creation of strangelets decreases at higher energies. As the LHC operates at higher energies than RHIC or the heavy ion programmes of the 1980s and 1990s, LHC is less likely to produce strangelets than its predecessors.[5]

RHIC has been around a long time and they were attempting to create mini "big bangs" and nothing disastrous happened there. ;)

The summary for the article:
...the concern is that micro black holes, if they are created and do not immediately decay, may remain within the Earth and begin accreting matter in the planet (CERN accepts this reasoning). CERN's response to this fear is that, if this was a problem, the high speed micro black holes created in nature would already have caused noticeable damage to bodies too dense for them to pass through, such as neutron stars and white dwarfs.

My opinion: there are crazy things passing through us and the Earth as we speak. We do not understand so many things that go on, and so while there is a minimal possibility that such scary things could occur, I do not see why so many accredited scientific associations would move forward with such a risky program.

Also, the people who head these groups to ensure the safety of the design are some of the most intelligent people in the world. If they trust in science, then we all should too.

Help the LHC
For those of you into the folding or SETI@Home projects, there is one for the LHC. You can find out more here (http://athome.web.cern.ch/athome/).

[Michael Ubaldi]

Fabulous! I'll be rereading this several times over the next few days, managing to absorb a tiny bit more each pass.

[Jes-ka]

If it doesn't make sense, I will try to fix it.

[TheMFShadow]

Fabulous! I'll be rereading this several times over the next few days, managing to absorb a tiny bit more each pass.

Same here. I do thank you for the explanation though. On the first browse through, it actually made a lot of sense to me. :)

[Ninja Raiden]

If it doesn't make sense, I will try to fix it.

It made a great deal more sense than "On Rationality"! ;)

[Michael Ubaldi]

Okay, the hamster wheel in my head has been spinning. What industry might these behaviors be able to assist, once understood and more easily reproducible? Propulsion? Energy generation? Ballistics?

[Jes-ka]

First of all, there is so much we do not know about particle/matter interactions. And so the Standard Model theory isn't perfect. Everything was mostly okay, but not great, so some guy named Higgs determined there was this other particle that sort of... dishes out mass to particles. It explained the interactions of the particles with different masses, it explained why certain particles had the masses they had, and it made a lot of sense on paper. And with that the hunt was on for this particle that had such powers.

Proving the existence of a particle we have never seen before may not seem so grand to us in our ordinary lives, and we may not really see a benefit from it now or several years from now, but the fact that we could a) create the Higgs Boson without ever seeing it naturally and by that measure b) complete the Standard Model, we have made huge monumental steps in physics towards many other things. Things like adding Gravity and thus propelling us toward a better Grand Unification Theory, or String Theory, or M Theory, whatever.

It all leads to understanding all matter interaction in the universe. Imagine what could be done/made at that point?

All in all, it is really what landing on the moon back in the 1969 is to us going to Mars. That was a huge deal back then. Not so much to people nowadays, but would we even be attempting that today if it were not for the Apollo missions?

This search for the Higgs Boson is going to be legendary (it's been going on for 30+ years, but who's counting?). There is always a sort of "fad" elusive particle in physics, and right now the popular one is the Higgs Boson because it seems most promising and most likely to actually exist, else why go to all this trouble?

Because the Higgs Boson really is worth all of the hype. If we prove it exists, we are proving why particles have mass. Unless, say, it exists but is not the harbinger of mass for all particles... in that case, every physicist's mind would be blown. That would probably mean the Standard Model is wrong and then it would be back to the drawing board!

[Jes-ka]

Same here. I do thank you for the explanation though. On the first browse through, it actually made a lot of sense to me. :)

My explanations are very simple and meant for a general understanding. So just be aware that the quantum world is insanely complicated and so I have left out a lot in order for it to be easily digestible. My quantum mechanics professor started our first class by saying "Welcome to the quantum world. Everything you know is wrong."

Because I want it to be simple, I may leave out things (I notice as I read my huge post over again), so don't be surprised if I add something. =\

I found this site (http://particleadventure.org/frameless/startstandard.html) that does a good job of explaining elementary particles and the Standard Model in way more detail. It even explains how a particle accelerator works. It's quite cute! So if you feel adventurous, I suggest spending some time there.

[TheMFShadow]

Stephen Hawkings put a bet of $100 that the LHC experiment would not find the scalar elementary particle.

[Michael Ubaldi]

All in all, it is really what landing on the moon back in the 1969 is to us going to Mars. That was a huge deal back then. Not so much to people nowadays, but would we even be attempting that today if it were not for the Apollo missions?Certainly not, nor would we have dozens and dozens of tools, utensils and concepts that directly resulted from spaceflight's research and experimentation.

This is exciting. Another question would be: how adaptable is the LHC? Is there use for it post-Higgs Boson; so many potential experiments, perhaps, that it's a kind of particle-accelerating jukebox?

[theempyrealwordsmith]

Stephen Hawkings put a bet of $100 that the LHC experiment would not find the scalar elementary particle.

Only $100?
You'd think he'd have more confidence than that.

[DreadNemesis]

More questions!

How does soap make things clean?
Why do earthworms have a hard time getting back into the ground after a rainfall?
What is black dirt? or in other words what is it made of?
How finite are finite resources? (like oil or metal ores and so on) in other words why haven't we run out yet?
Given a perfectly spherical planet could an object be made on said planet that would be completely flat?

[Jes-ka]

A colleague of mine linked me to this (http://www.cyriak.co.uk/lhc/lhc-webcams.html). Even physicists have a sense of humor. :D

[Jes-ka]

This is exciting. Another question would be: how adaptable is the LHC? Is there use for it post-Higgs Boson; so many potential experiments, perhaps, that it's a kind of particle-accelerating jukebox?

Well, particle accelerators are built to Energy specifications, so any experiments can be done as long as it requires energy levels within the capabilities of the accelerator. The LHC is designed to create energies from collisions of protons up to 14 TeV or Tera electron Volt.
That is about 2.24 x 10^-8 Joules, a very small number. (In my journey to convert this to Joules, I read that 1 TeV is about the energy of motion of a flying mosquito!)

Protons are pretty huge compared to their electron counterparts, so to get one to break up into its constituent parts (i.e. lego pieces) it is determined that you need to get it moving with energies up in the TeV's. This is just based on it's characteristic of being a hadron type of particle and with lots of fancy math it is easily determined what amount of energy you want to get the outcome you need.

From the wiki article:

Once or twice a day, as the protons are accelerated from 450 GeV to 7 TeV, the field of the superconducting dipole magnets will be increased from 0.54 to 8.3 tesla (T). The protons will each have an energy of 7 TeV, giving a total collision energy of 14 TeV (2.2 μJ).

The wiki article mentions that they will be doing ion collisions as well (main purpose of RHIC (http://www.bnl.gov/rhic/)), and I see there are new bits of info even as I write this post for you guys. Someone made a list of what questions the LHC should be able to answer (http://en.wikipedia.org/wiki/Large_Hadron_Collider#Purpose). I never really scrolled down that far before today. Ha!

Usually there are a few experiments going on at once. If you see the map of any accelerator, there are certain points at which the detectors for different experiments are located, for LHC they are labeled in a blue color on the main LHC website (http://lhc.web.cern.ch/lhc/). From there you can read about the different experiments going on. You can also find very detailed design specs there.

[Jes-ka]

Why is each snow flake a different shape yet we call ice a mineral because it has the following criteria: set chemical comopostion, occurs naturally, a set crystalline structure. If it's structure is consistant across the board, why is each snowflake built differently?

So, I know a lot about water but not necessarily about snowflakes. In everyday use, we just call the solid state of water "ice", but this is way too vague because ice comes in different types.

It can form different crystal structures depending on temperature and changes in that temperature. Some structures are stable and some are not. The most common is the hexagonal shape formed by 6 water molecules (see pics), and the gaps between them are why ice floats in water.

Snowflakes all form with a hexagonal shaped symmetry (see images). I also attached a pic of a water molecule with the angles included (harder to find online than I thought!).

Ice can form cubes as well as amorphous structures. It doesn't seem consistent but the temperature and how it is changing are what determines the type of structure it creates, and that is why snowflakes will look different.

Most snow flakes will be just a simple hexagon, but crystals can be supersaturated and when this happens to ice, it creates these funny branches. The level of this supersaturation is based on how each flake is prone to different temperature changes and pressure changes depending where it forms, where it lands, et cetera. And that is it!

These funny shapes are actually just defects in how the ice is forming. Some snowflakes have the solid hexagon shape in the middle, but then it becomes branches at some point where it became supersaturated... so its design is really just a story of what happened to the little flake of ice as it made its way to your yard. :)

[TheBadFish]

Snowflakes can be one of any number of shapes....The determining factor is the height and temperature at which it forms. Needles, broken dendrites (those funny little branches), graupel(collections of shattered snow pellets), hexagonal plates...etc are all possible. As usual Jess is correct.....she never ceases to amaze me. Yous one smart cookie woman!!!!

[DreadNemesis]

I've got another question to add to my most recent bunch: why does it get colder for a little while after the sun rises first thing in the morning? This may be a question more suited to Badfish than you Jes, I'm sorry to say.

[Pino]

"How do Frisbee discs fly?"

or...if you don't want to mention the copyrighted "Frisbee" name, how about "How do discs fly?"

[dropK1CK_ninJA]

I had another one...

When a space shuttle re-enters the Earth's atmosphere, friction creates heat to the underside of the shuttle. Why is it then that when we have cars and jets zooming around at high speeds they don't burst into flame due to friction as well?

[Lambduh]

What role does physics play in babymaking?

[Jes-ka]

What role does physics play in babymaking?

o.O

Weirdo...

[Jes-ka]

Um, physics question (maybe)... what happened all that hullabaloo over the "hole" in the ozone layer?

This may be more up BadFishes alley, but I will give this a try.

First of all, what is the ozone layer and why is it bad that there is a hole in it?
The ozone layer around our planet is a layer of the atmosphere that has the majority of the ozone molecules that exist... in the atmosphere. Think of the atmosphere around Earth like that 1-2-3 Jello from the 80's. There are many different types of gases that sit around, but because of temperature and pressure changes due to altitude these gases sift and sort themselves in layers.

The layers look something like the last attached image. The "ozone layer" resides within the Stratosphere. It is important because it acts as protection from the Sun's evil UV death rays. It absorbs the harmful rays and prevents them from hitting the Earth's surface and subsequently us.

How is ozone made?
Ozone is actually made of Oxygen, but rather than two bonded Oxygen atoms it is made of three. So while we need O2 to breathe, we need O3 to protect us all from the Sun who is obviously trying to kill us. Ozone is made when UV radiation hits an O2 molecule and then breaks it up into its individual atoms. Then these free oxygen atoms find other O2 molecules and add themselves as a third wheel. Bam, you now have a molecule of Ozone.

The important thing to understand here is that our Ozone layer can regenerate itself with the sun... like Superman.

So what is a CFC and why is it bad?
The Chlorofluorocarbon, aka the evil CFC, is a man-made compound that is a byproduct of stuff that is used for a wide range of things. The first came from a refrigerant chemical back in the 1930's! The name is for a category and not one particular molecule of anything, but this category is dangerous to the atmosphere because a CFC is very extremely stable.

Stable means that it can survive intact long enough to float way up into the Stratosphere (about ~15 years) where it can remain up there for up to 100 years. These CFC's then absorb the evil UV radiation and break up int Chlorine, which is ultimately like Kryptonite and the reason Ozone molecules are being destroyed way up there.

Ozone depletion is bad, mmmmmkay.
A few decades ago it was discovered that CFC's were making it up high enough to cause a problem in the Ozone layer. In 1985 it was discovered that it had depleted so much over the Antarctic that an actual hole had formed. People got busy and a couple years later the international treaty to ban CFC's (http://en.wikipedia.org/wiki/Montreal_Protocol) was initiated. It took several years but there are many countries involved and it has made a significant impact.

In 2003 it was determined by scientists that the Ozone depletion rate is slowing down significantly in the mid-latitudes and should be able to completely restore itself to normal levels in a few more decades. That's great, but we still have a problem with the actual hole in the Ozone layer.

The Ozone holes are in the polar regions. One big one over the Antarctic and one "dimple" over the North pole. You may be wondering why it is there and not above where most humans live, but the reason these holes exist has nothing to do with us. The temperatures of the atmosphere over the poles are the cause.

During Winter, clouds form up there in the Stratosphere. Chemicals that usually don't live in that region get pushed in there because temperature effects pressure changes and then a bunch of chemical reactions occur. At some point Chlorine is produced up there in enough of an abundance that it thins the Ozone layer enough to be considered an actual "hole". Two images show date progression of the hole over Antarctica.

But once the weather warms up in the Spring, things go back to the way they were and the hole begins to repair. Unfortunately the hole is still pretty big and I think I read somewhere it is the biggest it has been in a while. The biggest problem is that, if global warming is effecting everything, the Stratosphere will cool over time and thus begin this quicker Ozone depletion process, even in the mid-latitudes. *GASP*

Where is all this hullabaloo?
People are still up-in-arms, as they say. The thing is that Global Warming is a bigger issue at the moment, but people are still watching the Ozone levels in the Stratosphere.

If you feel so inclined...
For more reading check out the NOAA page (http://www.ozonelayer.noaa.gov/), the Wiki page on Ozone Depletion (http://en.wikipedia.org/wiki/Ozone_depletion), and the EPA site on Ozone Depletion (http://www.epa.gov/ozone/strathome.html).

[Jes-ka]

Let us discuss Sun Spots and how the affect us on the planet. Of course this is a multipart question that requires discussion of what sun spots are, their origins, our different spheres of protection and finally what gets to us ...

GOODNESS!! This topic is insanely complicated.

What are Sun Spots?
A sun spot is what we perceive as a dark blotch on the surface of the sun. I say perceive because it is not actually a "black" spot on the sun. It is just a slightly cooler area than the rest, and if I have not mentioned this yet, light/color represent temperature. I will go into that more when I answer the question about why stars are different colors.

You may have heard that our Sun goes through cycles. The 11 year cycle is how long it takes for the Sun to go through a period of a minimum and maximum of Sun Spots. After 11 years it will "relax" and then it's magnetic field changes direction. Then it has another 11 year cycle of Sun Spots, then relaxes. The magnetic field changes direction again. It takes 22 years for the Sun to go through what is considered a complete Solar Cycle.

What makes a Sun Spot?
If you check out the image I attached with the three suns, it will help explain this part.

Here on Earth the crust is solid so when the Earth rotates... everything goes as one. You don't see South America rotate slower than North America (relatively speaking), and so on. But the Sun is different because it is made up of gas! It is all free to move and rotate as it pleases, so it follows the concept that the gas at the poles moves slower than the gas at the equator (that is why the picture shows the magnetic field lines skewed as the Sun rotates).

In the third part of that image, you see the magnetic lines skewed a whole bunch. They just go crazy! Since they are moving at different speeds depending on the latitude, we get a lot of magnetic flux (flux is just an increase or decrease in the strength of the field). The flux itself will actually get tangled up after a while and then they get pissed off and turn inward to the surface.

This injection of magnetic flux interferes with how the sun is churning its star-stuff on the inside and makes the surface temperature drop slightly (about 1,000-1,500 K less than the surrounding area). Since the temperature drops a little, the light isn't as bright. Hence you get a dark spot.

Throughout the 11 year cycle, the magnetic field gets crazier and so the number of Sun Spots increases up to a maximum number, then it reverses and eventually relaxes to a point where the magnetic field lines are straight again. This is the minimum point of the cycle.

The Sun's equator acts as a mirror, so when a Sun Spot occurs in the northern hemisphere, it also occurs in the same place of the southern hemisphere. You can see this represented in the orange chart I have attached.

How do Sun Spots effect us?
Space weather is pretty complex. Obviously solar radiation (light) reaches us and effects our lives. We wouldn't be able to see anything without it! But this solar radiation isn't all butterflies and gumdrops. If it weren't for the Earth's magnetic field, our atmosphere would get ripped away and we would end up just like Mars. Because that is just what happened to Mars!

So, check this. Some dudes in the 70's noticed that when the Sun had a maximum number of Sun Spots, there was a noticeably higher amount of radiation pouring over us. Check out the black and white chart. You will see the number of Sun Spots of a very long time (Sun Spots have been visible and recorded for roughly 300 years!). Since it is hard prove correlations between the activity of Sun Spots and weather or other phenomena here on Earth, it isn't just assumed that it has a direct effect on Earth.

But scientists do think that the weather on the Sun effects us in many ways, for example the global warming cycle and other weather patterns. To me it just seems that changes in the radiation is what effects us. Sun Spots, Solar Flares... these all seem to change how much radiation we receive. The radiation then has to interact with the Earth's magnetic field (an entire discussion in itself). There are so many satellites up there now that I am sure we will figure out some kind of correlation, but it just seems there isn't a good solid theory about it.

This is basically what we know: Solar radiation does stuff to us.

If you feel so inclined...
If you are interested in following the changing face of the Sun, I recommend SpaceWeather.com (http://spaceweather.com/).

[Vaulter85]

I got one...


How does the Flux Capacitor work?

[Jes-ka]

I got one...


How does the Flux Capacitor work?

Uhhh lol a very interesting question. I think I can explain the idea behind it's purpose, I need to refresh my knowledge of Back to the Future first.

In the meantime, you could buy one here (http://www.amazon.com/Back-Future-Flux-Capacitor-Replica/dp/B000ZM0Q4I/ref=pd_bbs_sr_1?ie=UTF8&s=toys-and-games&qid=1229018185&sr=8-1)and just take it apart. ;)

[Shockman]

Uhhh lol a very interesting question. I think I can explain the idea behind it's purpose, I need to refresh my knowledge of Back to the Future first.

In the meantime, you could buy one here (http://www.amazon.com/Back-Future-Flux-Capacitor-Replica/dp/B000ZM0Q4I/ref=pd_bbs_sr_1?ie=UTF8&s=toys-and-games&qid=1229018185&sr=8-1)and just take it apart. ;)

Save yourself the time of watching the movie again.

You can refresh your memory by slipping in the bathroom and landing on the toilet with your head. :p

[Vaulter85]

Save yourself the time of watching the movie again.

You can refresh your memory by slipping in the bathroom and landing on the toilet with your head. :p

lol.

$500 for a flux capacitor! Wow! Opening a rift in the space time continueum isn't cheap.

[Jes-ka]

lol.

$500 for a flux capacitor! Wow! Opening a rift in the space time continueum isn't cheap.

Actually it is quite cheap... compared to say, the LHC. XD

[Shockman]

Actually it is quite cheap... compared to say, the LHC. XD

Flux capacitor - $499.99

1981 DELOREAN DMC-12 Sports Car - $38,850.00

Ripping a whole in the space time continuum to get back to 1985 - PRICELESS!!

LOL:D

[Jes-ka]

Ninja, I will answer each of yours independently.

1. Why do the stars appear in a variety of colours?

So back in this (http://game-and-player.com/forums/showpost.php?p=6882&postcount=49)post I had explained why light pollution can make it hard for us to see the billions and billions of stars that are out there.

Billions and Billions
If you ever get a chance to see more than a few stars near each other, you have probably noticed that they emit different hues. Some are bluish, some are reddish, and others seem to be very white. These are the three general classifications of a stars temperature. If you ever take a basic Astronomy class you will learn to call them white-hot, red-hot and blue-hot. But stars emit color from the entire spectrum of light.The only limiting element to detecting color in stars with the naked eye is your eyesight!

The Hertzsprung-Russel Diagram
In Astronomy you will learn to read something called an H-R Diagram (H-R stands for Hertzsprung -Russell, two dudes who organized this mess) which tells you roughly what temperature a star is, what stage it is in its lifespan, it's future stages of life, and what elements it is made of. All very useful information when studying the universe in depth.

Attached is an H-R diagram. It is very pretty, but you can see that there is a pattern based on the way they are plotted. To read this chart, each point is a star. Each purple line is a lifespan. Stars are born incredibly hot and very very bright, so the lifespans begin in the top left and follow a trend to the bottom right. Some stars can jump from being a Main Sequence to a Giant, it all depends on the mass of the star. Often after the Red Giants burn out, you can end up with a teensy white dwarf, the elderly of the star population.

Yes yes, but the color! What about the color!
Notice that in this diagram, the dots have a color! That color is based on what you see (depending on how well you can see color variations) which comes from, what? ...Temperature! You can check a color, say yellow, and look up to see what range of temperatures the yellow color covers. It looks to be between 6,000K and about 4,500K.

So from this chart we can roughly guess how hot a star is, but there is something else we can find out. As stars pass through different stages of life, it produces different elements. Using Stellar Spectroscopy, one can determine what elements are being burned at any given time.

How does that work exactly? When you excite anything, i.e. heat it up a lot... like in the sun, that anything will radiate energy in the form of light. Using a prism, the light will be broken up into it's individual parts. This is called it's Emission Line.

Here (http://jersey.uoregon.edu/vlab/elements/Elements.html)is a site with a periodic table that you can click an element and it will show you the Absorption and Emission lines.

Example: Hydrogen. You will see two dark blue lines, a cyan blue, and a red! No other element will have this fingerprint at all! Each line of color is a wavelength f light measured in nano meters (nm). If you observed the element in its excited state and were able to see the light it gave off without a prism, you would see the color that it's emitting the most of. In the case of our sun, that color is yellow.

I am sure you are wondering now what is the difference between absorption and emission lines? it is actually very simple! You should able to see on the interactive periodic table that by changing from absorption to emission you just get the opposite. What causes the difference is that Absorption lines come from viewing the light filtered through some sort of cooler gas (between us and the star), and then the Emission lines are unfiltered. You would only see emission lines in a lab situation unless you somehow created a filter of gas that was cooler than your excited element!

What about our Sun?
At the very very top of the chart there is a special letter classification that was invented to label stars based on this chart: OBAFGKM. Our Sun is considered average in type and age. It is a GIV Yellow Main Sequence star (the IV is just a more precise measure along this particular scale). Basically it would sit somewhere in the yellow region of the main sequence line. It is about halfway through it's lifespan, meaning it is already around 4.5 billion years old and it has about that much more to go before it swells up to Red Giant status! Probably not good for us. =\

If you feel so inclined...
Here (http://sunshine.chpc.utah.edu/labs/star_life/hr_interactive.html)is a site with an interactive H-R diagram. You can answer questions based on their example stars and hopefully this will give you a better understanding about the life of a star!

[QuestionMarkMan]

Oh I got a question!!!!

The closer I get to a black hole, the faster time will speed up around me correct? So if it were possible to stand in the center of a black hole without being ripped into atoms, would time speed up infinitely? What would that mean? Would time end?

My head hurts now :(

[Michael Ubaldi]

I'll never forget the mnemonic for spectral class: "Oh, Be a Fine Girl — Kiss Me!"

[Jes-ka]

Oh I got a question!!!!

The closer I get to a black hole, the faster time will speed up around me correct? So if it were possible to stand in the center of a black hole without being ripped into atoms, would time speed up infinitely? What would that mean? Would time end?

My head hurts now :(

Consider the Twin Paradox (http://en.wikipedia.org/wiki/Twin_paradox), a very famous though experiment by Einstein. It is best explained like this: A pair of twins grow up and one decides to take a trip on a spaceship. The other stays on Earth. He or she may only be out traveling for what seems like a year and so they return to Earth. They discover that they are much much younger than the twin who stayed and had plenty of time to raise a family and perhaps even have some grandchildren.

Interesting? Quite. The problem here is that once the space-faring twin leaves Earth, they are no longer in the same Inertial Reference Frame. It is argued that if both twins were aware of the others watch (for say date and time) they would both observe that the other is aging less than themselves. Weird? Oh yes.

Staying within the same Inertial Reference Frames are basically what will keep things symmetrical. But it is not impossible to measure velocities and things like that because you still have relative speeds, even outside an Inertial Reference Frame. The key word here is relative, of course. What is observed by Twin #1 may not be the same if you change the frame of reference to Twin #2.

So why does time seem to accelerate when you compare the two? Time actually does not accelerate like velocity does. It is something you would most likely not notice. To both twins, neither experienced anything out of the ordinary. They feel they age at a normal rate. The asymmetries come from observations by a different frame of reference.

How does this relate to your question? If the Twin Paradox is technically true, would you notice time changing in any way? You would need an outside observer looking at a special readout of your watch in order for anyone to know what crazy stuff was happening to you. What do you think about that?

[Jes-ka]

Why do you get a sense of vertigo when you look up at the sky?

What is Vertigo?
It is when it feels as though you are moving or your surroundings are moving. If you ride a merry-go-round and then get off, the feeling you get afterwards is similar to Vertigo. It is most commonly caused by a medical condition, either migraines, decreased blood flow to the brain, or even inner ear infections.

Keep in mind the feeling of Vertigo is not the same is feeling dizzy. Dizziness feels more like you are about to fall down and you may also feel lightheaded. It's a little harder to describe what it is to feel dizzy since it can vary slightly. Both symptoms are related to issues of balance.

How our body works.
Most people are aware of the Inner Ear. It is a very important part of keeping balance. Hence when something goes wrong with it (such as an infection), it can mess up our perceptions of our own movement.

Our eyes are a major proponent in keeping balance. Dancers and ice skaters who can spin and spin for days (http://www.youtube.com/watch?v=G8_MNDNoVqg) without getting dizzy use a method of turning their heads faster than their bodies and always focusing on one point in front of them. By doing this they are using their eyes to tell their brain not to get dizzy!

Via our extremities, our brain can determine the orientation of our bodies. This information is very important because at any moment their positions may need to change in order to keep us from falling.

All of these things are important because they give information to our brain which ultimately determines what to do. If any information from these parts gets corrupted (i.e. blood flow decreases, or an inner ear infection) you can experience problems with balance.

What about the sky?
I remember one summer I spent in Colorado. There were hardly any trees where I was and I would lay down on the grass at night and gaze at the stars. If you looked in such a way that you blocked any surrounding buildings from your field of view, you felt as if you were about to float right off the ground and up into the sky!

I also remember playing Ocarina of Time, and I was leaving that area with those Gorons and I decided to jump off a higher part of the mountain down to the bottom. I picked a terrible place to jump from because I fell to my death, but during the fall I felt that gross feeling in my stomach much like when you ride a roller coaster. My brain really thought I was falling! (This also happened once in Crackdown)

These feelings all come from confusing your brain by giving it unusual information. By removing all surrounding objects that may clue your brain in that you are still standing on solid ground, you can make yourself feel funny! I'm not sure if this is similar to the situation you are describing, but consider that some people are more sensitive to these input changes than others.

I hope this helps. :)

[Pino]

Consider the Twin Paradox (http://en.wikipedia.org/wiki/Twin_paradox), a very famous though experiment by Einstein. It is best explained like this: A pair of twins grow up and one decides to take a trip on a spaceship. The other stays on Earth. He or she may only be out traveling for what seems like a year and so they return to Earth. They discover that they are much much younger than the twin who stayed and had plenty of time to raise a family and perhaps even have some grandchildren.

Interesting? Quite. The problem here is that once the space-faring twin leaves Earth, they are no longer in the same Inertial Reference Frame. It is argued that if both twins were aware of the others watch (for say date and time) they would both observe that the other is aging less than themselves. Weird? Oh yes.

Staying within the same Inertial Reference Frames are basically what will keep things symmetrical. But it is not impossible to measure velocities and things like that because you still have relative speeds, even outside an Inertial Reference Frame. The key word here is relative, of course. What is observed by Twin #1 may not be the same if you change the frame of reference to Twin #2.

So why does time seem to accelerate when you compare the two? Time actually does not accelerate like velocity does. It is something you would most likely not notice. To both twins, neither experienced anything out of the ordinary. They feel they age at a normal rate. The asymmetries come from observations by a different frame of reference.

How does this relate to your question? If the Twin Paradox is technically true, would you notice time changing in any way? You would need an outside observer looking at a special readout of your watch in order for anyone to know what crazy stuff was happening to you. What do you think about that?
I believe I was taught that when past the event horizon, you approach a point of singularity. If such an observer were to be at the center of the black hole, they would surely be at the theoretical point of singularity. Thus, with the volume of space now zero, would not the speed of light be infinitely slow (if not zero) as the distance a photon travels per relativistic second approach zero? I am only saying this because to me, velocity is simply the distance changed divided by the change in the relative time (d/t). But, as 'd' gets infinitely smaller, this fraction approaches zero, no?

[Jes-ka]

I'm going to re-address the Black Hole stuff shortly. I'm just getting over Bronchitis so I really didn't feel like I could answer questions coherently.

[Jes-ka]

So after getting sidetracked, I am going to be unemployed very soon (a good thing) and I will have time to work on this writing project of mine. I will answer all the questions here as preparation.